1. Field of Invention
This invention relates to attractants for bees in the genus Osmia, particularly Osmia lignaria, the blue orchard bee. The attractants can be useful for encouraging the bees to return to nesting structures and to make a nest in nesting structures. The invention also relates to a method for reducing dispersal of Osmia spp. by applying the attractants to an object or area. The invention also relates to a method of attracting Osmia spp. to an artificial nest site by applying the attractants to the artificial nest site.
2. Prior Art Description
More than ninety crops in the United States are pollinated by the European honey bee, Apis mellifera. The recent concern for honey bee health and the growing demand for more bees have increased interest in pollination with non-honey bee species. In fact, other bees are now being used and are greatly beneficial to certain crops. For example, Megachile rotundata, the alfalfa leafcutting bee, is a commercial pollinator for alfalfa, canola, trefoil and carrot seed. Osmia lignaria is a native, solitary species and an excellent pollinator of almonds, cherries, apples, and pears (Torchio, Proc. Ent. Soc. Ont. 118:111-124 (1987); Torchio, Environ. Entomol. 19:1649-1656 (1990); Bosch and Kemp, How to Manage the Blue Orchard Bee as an Orchard Pollinator, Sustainable Agriculture Network, National Agricultural Library; Beltsville, Md. (2001)). In fact, studies have shown that use of O. lignaria as a pollinator can increase yields over honey bee pollination in almonds, apples, and cherries (Torchio (1987); Torchio, J. Kansas Entomol. Soc. 58:448-464 (1985); Kuhn and Ambrose, J. Kansas Ent. Soc. 57:169-180 (1984); Bosch and Kemp, Bee World 80(4):163-173 (1999); and Bosch, et al., J. Econ. Entomol. 99(2):408-413 (2006)). Furthermore, O. lignaria females forage and pollinate under cloudy skies and at lower temperatures than most other bees and rarely sting.
Management systems for cavity-nesting bees are being developed for use in crop pollination. Osmia spp. are of particular interest because some species, e.g., O. lignaria, O. cornuta, O. cornifrons, and O. bicornis, emerge in the early spring and can be used specifically for fruit and nut production of spring-flowering crops such as almonds, apples, cherries, and blueberries (Bosch and Kemp (1999); Bosch and Kemp (2001); Sekita, et al., Acta Horticulturae 561:303-307 (2001), Bosch, et al. (2006); Maccagnani, et al., Bulletin of Insectology 60(1):77-82 (2007), Gruber, et al., Apidologie 42(5):564-576 (2011), Artz, et al., Insect Conserv. Diver. 6:715-724 (2013)). These bees are holarctic in distribution (Michener, The Bees of the World, 2nd ed., Johns Hopkins U. Press (2007); Rightmeyer, et al., ZooKeys 60:37-77 (2010)).
Several difficulties exist in commercially managing O. lignaria. One difficulty is that the bees tend to disperse from their release site (as much as 50%) (Torchio 1982. J. Kansas Entomol. Soc. 55:101-116; Torchio 1984. J. Kansas Entomol. Soc. 57:689-694, Stanley, et al. 2011). Mortality of bees or their larva in previously used nesting structures is another barrier to commercial management of O. lignaria and other Osmia spp. under commercial development. Previously used nesting structures may contain diseases, parasitoids, and pests that infect or prey on the bees or their larva and reduce the bee population in subsequent years (Bosch and Kemp, 2001; Pitts-Singer, J. Apic. Res. 43:40-46 (2004)). Mortality may possibly be reduced by the bee manager using new, clean cavities in the nesting structure (see, e.g., Bosch and Kemp, 2001); however, that may lead to an increase in bee dispersal, the previously mentioned difficulty.
One potential solution to these problems is to increase the “attractiveness” of the structure of a natural or artificial nest site, thereby increasing the pollinating efficiency and reproduction of the bee. If more bees remain in an orchard at the artificial nest sites, then they could pollinate more of the crop. Also, more bees could produce more brood that would be used during the following crop season. In a laboratory bioassay, it was demonstrated that O. lignaria females in a Y-tube respond significantly to empty female cocoons and also tend to respond to a chloroform:methanol extract of cocoons when exposed to the air passing over the cocoon or filter paper containing the cocoon extract (Pitts-Singer, Environ. Entomol. 36: 402-408 (2007)). However, the use of empty cocoons or crude cocoon extracts as attractants is undesirable. A pre-determined chemical composition that can be reliably manufactured and reproduced, and that can offer a constant level of efficacy, may be a stronger attractant and cost less than using empty cocoons or crude extracts.